It is narrated from Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever initiates a good practice will have its reward for as long as it is acted upon, in his lifetime and after his death, until that practice is abandoned. And whoever initiates an evil practice will bear its sin until that practice is abandoned. And whoever dies guarding the frontier (murabit) in the way of Allah, the reward of the murabit will continue to flow for him until he is raised on the Day of Resurrection."
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18404